Intelligence, IQ science
& cognitive research

The correlation is real — but weaker than you might expect, and it fades above a threshold of around 120. What the evidence actually shows about IQ and life outcomes.

Brain training apps make big promises. Education, exercise, sleep, and nutrition show real but modest effects. The evidence-based breakdown of what works and what doesn't.

Accuracy, cost, purpose, and when you actually need a professional test. A clear comparison to help you decide which type of assessment is right for your situation.

IQ scores aren't fixed. Fluid intelligence peaks in your mid-twenties, while crystallised knowledge keeps building into your sixties. What the research says about IQ across the lifespan.

Einstein 160, Hawking 160, da Vinci 220 — where do these numbers come from? We break down which famous IQ claims have evidence and which are folklore.

WAIS-IV, Stanford-Binet, Raven's Matrices, Cattell Culture Fair — each measures intelligence differently. Which test is right depends entirely on what you're trying to know.

Mensa requires the top 2% — but that's not a single fixed number. It depends which test you take, which scale it uses, and whether it was proctored. The complete guide to qualifying.

Working memory strongly predicts IQ. But can you improve it? The evidence on n-back training, dual-task practice, and the crucial near vs. far transfer problem.

International IQ comparisons are widely cited and widely misinterpreted. The data shows large environmental effects — and the methodology has serious limitations worth understanding.

Most gifted programmes use a threshold of 130, but the research on outcomes is more complicated. What giftedness actually means, and the limitations of defining it purely by IQ.

When is it appropriate to test a child's IQ? Which tests are designed for children? And what should — and shouldn't — you do with the result? A guide for parents.